There are some dialogues, moments in movies and TV series that has a profound effect on me and I keep remembering them now and then. Here are few of them:

1. Harry Potter and the Half Blood Prince - Harry and Slughorn

Harry Potter is tasked by Headmaster Dumbledore with getting certain information from Professor Horace Slughorn, which he is deeply ashamed of sharing. Slughorn avoids Harry when he knows of this. But Harry manages to corner him one time in Hagrid's cabin. Both slughorn and Hagrid are drunk, discussing about dear things that they had lost. Hagrid telling about how he got Aragog, his pet giant spider (Acromantula). Slughorn about a fish Francis that he owned, but disappeared one day. Midway, Hagrid is knocked out by the excess alcohol. Slughorn then turns to Harry to tell about Francis -

"It was a student who gave me Francis. One spring afternoon, I discovered a bowl in my desk.. just a few inches of clear water in it. Floating on the surface was a flower petal. As I watched, it sank.. just before it reached the bottom.. it transformed .. into a wee fish. It was beautiful magic.. wonderous to behold. The flower petal had come from a lily – your mother. The day I came downstairs .. the day the bowl was empty.. was the day your mother.."

The way he expressed how much he liked his student and her death was quite touching. Lily, Harry Potter's mother was one of his all time favorite students. It would have been an loss for him when Voldemort killed her. This dialogue is not in the books, but is an wonderful addition in the movie. I never liked the HBP movie that much other than this dialogue.

2. Star Trek Voyager - Captain Janeway and Commander Chakotay

Ths ship USS Voyager is on a 75 year trip back home, after being lost 75,000 light years from home. Headed by Captain Kathrine Janeway and Commander Chakotay, they encounter new alien races and lifeforms. During one such encounter, Janeway and Chakotay are forced to stay behind in a planet due to an alien disease that would kill them if they leave the planet. The crew of the USS Voyager are ordered to continue their course home. Being alone in a planet, they develop closeness for one another. Captain Janeway resists getting close with her first officer and tries to define "parameters" for their relationship. But Chakotay says that he cannot -

I can tell you a story - its an ancient legend among my people. Its about an angry warrior who lived his life in conflict with the rest of his tribe.. a man who couldn't find peace even with the help of his spirit guide. For years he struggled with his discontent. The only satisfaction he ever got came when he was in battle. This made him a hero among his people, but the warrior still longed for peace within himself. One day he and his war party were captured by a neighbouring tribe led by a woman warrior. She called on him to join her because her tribe was too small and weak to defend itself from all its enemies. The woman warrior was brave and beautiful and very wise. The angry warrior swore to himself that he would stay by her side doing whatever he could to lighten her burden. From that point on, her needs would come first.. and in that way the warrior began to know the true meaning of peace.

Janeway realizes midway that he is talking about themselves – starting with the union of the crew of the Starfleet and the Maquis rebels in the Delta Quadrant. She gives in and they closer. They spend a few more days in the planet, until the crew of the USS voyager return with a cure for their disease. They are able to leave the planet and resume their professional relationship and leave their romantic feelings behind in the planet.

A lot of people are unhappy that there was no closer relationship shown between Janeway and Chakotay. But the actress who played Janeway didn't want a closer relationship potrayed with her first officer onscreen because it would undermine her role as a captain. Personally I am okay with that.